Wetting Agent Program and Irrigation Effects On Putting Green Performance.

Golf course superintendents often use modern technologies, such as wetting agents and weather station data, to conserve irrigation resources.  Irrigating based on evapotranspiration (ET) losses will help ensure an appropriate amount of water is available to maintain visual turf quality while keeping the putting surface firm for desired ball roll and shot holding characteristics.  The objective of this research is to evaluate the effectiveness of commonly-used wetting agent products while irrigating at various levels of replacement ET on a sand-based creeping bentgrass (Agrostis stolonifera) putting green.  The study was a split plot design with irrigation treatments applied in whole plots at 50%, 75%, 100%, and 125% ET and six wetting agent treatments applied as subplots within.  Turf quality and color declined significantly when irrigation was applied at less than 75% ET.   Among irrigation treatments, 50% ET had more localized dry spots (LDS) than any other plots.  Similarly the untreated control plots had more LDS than all wetting agent treatments regardless of the irrigation level.  Volumetric soil moisture evaluations at various depths indicated that the use of wetting agents did not affect the overall volumetric water content average, but improved uniformity of rootzone moisture across all irrigation levels.  Wetting agent treatment did not have a significant effect on surface hardness when sufficient irrigation was applied, but decreased hardness at the 50% ET irrigation level.  There were no effects of irrigation or wetting agent on golf ball roll distance.  A favorable playing surface is attainable using less irrigation resources when wetting agents are applied.